Method and apparatus for forming concrete pipes



Feb 12, 1952 H. x. Escl-ENBRENNER 2,585,756

METHOD AND APPARATUS FOR FORMING CONCRETE PIPES Filed Aug. l1, 1947 3 Sheets-Sheet l wve/wbw HcforX Eschenbrezzer www Feb- 12, 1952 H. x. EscHENBRr-:NNER 2,585,756

METHOD AND APPARATUS FOR FORMING CONCRETE PIPES Filed Aug. ll, 1947 3 Sheets-Sheet 2 Feb- 12, 1952 H. x. ESCHENBRENNER 2,585,756

METHOD AND APPARATUS FOR` FORMING CONCRETE PIPES 5 Sheets-Sheet 5 Filed Aug. 11, 1947 gwuwwbo'b HecforX Esczcnbzvezzner b o B a o o a 9 b t n 0 0 l 0 a l 0 B o 0 o 0 b n B a O 0 l 0 l o l n b 0 l l 6 I 4be had throughout the finished pipe. .paratus necessary for such tamping operation `was generally subject to many objections, due

Patented Feb. 12, 1952 A-UNirED STAT-ss PATENT oFF-ICE METHOD AND `APPARATUS FOR'FORMING CONCRETE PIPES Hector X. Eschenbrenner, Columbus, Ohio Application August 11, 1947, Serial No. 767,928

(Cl. y25-3(`9) 3 Claims.

1 The' present invention relates to apparatus and methods for forming concrete pipe, andl has particular reference to improved apparatus and methods for the lformation of concrete pipe from what is termed a wet cementitious mix which has long been known to produce concrete articles possessing a high'degree of strength, durability,

and a-su'perior surface nish.

Heretofore, in the formation of concrete pipe `with machines it'has been customary `to utilize what is known in the-art-as dry mix, wherein theliquid content of the mix was held to a substantial minimum, in `order that after initially .forming 'the pipe the same might possess suf- -ficient rigidity to retain its shape and be able to stand alone upon the early removal therefrom of the associated inner form apparatus, and without necessitating a lengthy setting or dryingperiod prior to such removal. Also in the formation 'of concrete pipe from a dry mix, it was necessary to tamp or pack the mix 'as the same was being introduced'to the forming apparatus, in order `that a uniform density might The aptoits cumbersome nature, its susceptibility to breakage, and its interference with the metallic reinforcing vmembers generally positioned within vthemix as the same was being formed into pipe configuration. Further, the exterior` surfaces of pipes formed from a dry mix were characterized by their rough finish, which was objectionable from the standpoint of sanitary engineering, as such roughness subsequently tends to disturb the flow of 'liquids through such pipe and enhances the accumulation of moss and other foreign matter upon the inner surfaces of th In the past, the primary objections to forming concrete pipe from what is generally termed a wet mix, wherein the liquid content of the mix is in excess of that actually required for the normal setting and molding of the cement, arose through the difficulty of removing the excess Aliquid during or after initial forming operations.

Failure to remove substantially all of the excess liquid from the mix resulted in a greatly increased setting time prior to the removal of the associated forms from the molded pipe, because of the fluid or semi-fluid nature of the overall mix. Also, the presence of excess liquids during hardening stages tended to produce a brittle and somewhat weakened pipe, due to the formation of occluded air spaces within the mix upon evaporation lof the excess waterpresent therein.

Accordingly, it is van object of the presentinvention to provide improved` apparatusfand methods for forming vconcrete pipe ypossessed of superior characteristics, 'as'to structural strength and surface finish, by utilizing a so-called "wet cementitious mix, wherein'the excess liquids-carried within the mix are removed during vinitial forming operationsthrough the medium of negative .pressures applied through atleast oneof the formmembers of the associated molding machine to substantiallyftheentire inner surface of the mix while-the same is undergoing rotational movement to `insure an even .density throughout the nishedpipe.

It 'is another object of this invention to provide -a concrete pipe-forming ymachine wherein the usual tamping apparatus, characterized by its many objectionable features, is eliminated -en- 'tirely,'due to the fluid nature of the wet mix, and its ability to uniformly pack litself into a dense mass independently of such tamping apparatus.

It is a further object'of this invention to provide a concrete pipe-forming machine embody-I ing an outer-cylindrical and rotatable form, and a relatively stationary cylindrical inner core disposed in `concentrically spaced relation tothe outerform and defining therewith a cylindrical pipe-forming chamber for the reception of a wet cementitious mix, and wherein thecore of the machineis formed internally with a suction chamber communicating with the pipe-forming chamber for withdrawing excess water fromja wet mix disposed therein during the initial formation and rotation of the pipe-forming mix.

It is still another object of this invention to provide improved methods for the formation of concrete articles possessing Asuperior characteristics by subjecting a cementitious mix upon initial formation to rotational movement 4to insure an even and uniform density throughout the Imix, at the same time subjecting substantially the entire surface of the mix to reduced Vpressures to remove excess'liquids therefrom, and simultaneously vibrating the mix to additionally insure superior density qualities within the objectto be formed.

Yet another object of this invention is'to provide means whereby the action of reduced pressures upon the mix is evenly distributed `over the entire area of the mix rather than being alternately concentrated upon any one particular area, in order to avoid uneven displacement of the ymix patches throughout the formed article.

For a further and more detailed understanding of the present invention and the additional objects and advantages arising therefrom, reference is made to the following description and the accompanying drawings wherein:

Fig. l is a side elevational View of a concrete pipe-forming machine embodying the aspects of the present invention;

Fig. 2 is a front elevational view of the machine disclosed in Fig. 1;

Fig. 3 is an enlarged medial transverse vertical sectional view taken through the core, outer form, and turn table mechanisms embodied in the present pipe-forming machine;

Fig. 4 is a horizontal sectional view taken along a plane indicated by the line 4-4 of Fig. 3;

Fig. 5 is an elevational view of the cylindrical core embodied in the present machine;

Fig. 6 is a horizontal sectional view taken along the line 6-6 of Fig. 3;

Fig.' 7 is a fragmentary vertical sectional view 4taken through a slightly modif-led assembly,

wherein the cylindrical outer form is perforated.

Referring now to the drawings, the numeral I designates the frame structure of the present pipe-forming machine, which structure comprises a plurality of vertically arising side members II, and a number of upper cross members I2. The vertically arising end members of the frame are embedded in and supported by a floorlevel foundation I3. Arranged slightly above the foundation I3, in a horizontal plane, is a circular turn table I4 which is supported for rotational movement within an axially disposed stationary bearing member I carried below the floor level upon suitable subterranean angle iron beams I6. The table is formed centrally with a circular bearing sleeve I4b which lits within the bearing member I5 to provide for rotational movement within the table relative to the bearing member. An annular thrust bearing I5a. is interposed between the upper surface of the member I5 and the lower surface of the turn table to minimize friction between these parts. The turn table I4 is further provided at its underside with a beveled ring gear I'I which is maintained in meshing engagement with the teeth of a smaller beveled pinion I8 carried upon the outer end of a driven shaft I9. The lshaft I9 is, in turn, driven through a series of reduction gears whose driving power is furnished by an electric motor 2l suitably supported upon the frame structure I0.

Disposed upon the upper cross members I2 of 'the frame is a motor driven winch 22, which,

pair of the vertically arising side members II ofr theframe. -The shaft 24 is disposed in vertical axial alignment with the rotatable turn table I4, in order that the core structure carried at its lower end may descend and arise in axial alignl ment with the table.

The upper surface of the turn table I4 is formed with a plurality of cleats or lugs I4a upon which is supported the lower edge of a cylindrical outer form member 26. The outer form 26, as is the usual case, is dividedv into al tachable sections which are united by means of externally disposed locking devices 21. The outer form 26 is adapted to be positioned in vertically arranged order upon the lugs of the turn table I4, and is maintained in axial alignment therewith by means of positioning studs 28 carried upon the upper surface of the lugs I4a. As before stated, a cylindrical core 29 is rigidly carried at the lower end of the vertically arranged shaft 24, and is movable in a vertical plane in alignment with the axis of the turn table I 4. The diameter of the core 29 is substantially less than that of the outer form 26, and when lowered to its pipe-forming position, as disclosed in Fig. 3 of the drawings, the same is disposed in spaced concentric relation to the outer form, and thereby defines with the outer form an annular cylindrical chamber 30 for the reception of a wet cementitious mix which is introduced within the chamber by way of a feed spout 3| communicating at its upper end with a feed hopper 32 which is carried by the frame structure, and from whence the mix may be discharged to the spout by means of a suitable manually controlled metering valve, as indicated at 32a.

As shown in Fig. 3 of the drawings, the lower end of the mix-receiving chamber 30 is closed by an annular pallet 33 which is detachably supported upon an annular ledge 34 which is secured to the lower inner surface of the outer form 26. The pallet 33 possesses a substantially Z-shaped cross sectional configuration and serves to support the lower end of the column of mix positioned within the chamber, and to form the lower end into spigot configuration corresponding to the enlarged upper bell-end of the nished pipe provided by a relatively enlarged flange 35 carried by the upper end of the core. By this means, the individual pipe sections formed within the machine are provided with cooperatively itting bell and spigot ends. The pallet 33 is formed so as to closely conform to the outer diameter of the core 29, in order to prevent leakage of the wet mix from the lower end of the chamber 30, during initial pouring and subsequent rotation of the mix and outer form.

The upper end of the cylindrical core 29 is closed by means of an im-perforate upper end plate 36, to which is secured,l by means of a sleeve 31, the lower end of the lift shaft 24. The side walls of the core are formed with a series of vertically aligned perforations 38 which provide communication between the mixreceiving chamber 30 and the interior chamber of the hollow core. The interior bottom wall 39 of the core is inclined toward its center, at which point the lower wall 39 is provided with an axially disposed passageway 40 which is defined by a downwardly extending and axially disposed sleeve 4I formed integral with the bottom wall. The lower portion of the sleeve 4I is receivable in, and formsy a slip joint with a bell shaped socket member 42 carried by and disposed axially of the main bearing member I5. A compression gasket 4 3 is disposed at the lower tapered shoulders of the socket member 42 to provide an airtight seal between the two members when the core 29 is lowered into position, as indicated in Fig. 3. The socket member 42 is formed with a tubular extension 44 which extends below the main bearing member I5 and its supporting angle iron means I6, to connect with a suction conduit 45, by means of a threaded joint 46. The opposite end of the suction conduit 45 is'connected with and forms the intake side of a suit- 58 able lmotor drivenv suction pump 41 positioned 'withln'af subterranean-sink 48 disposed below the foorflevel'foundation I3, upon which the macchine-'is supported. -Thus it will be seen, that as the core-29 is lowered to its. pipe-forming position, as indicated in Fig. 3, an air-tight communication is obtained between the interior chamber of the core and the suction pump 41, and uponoperation of the latter the pressure v-within'the*interior of the core will be reduced --whereby substantially'the entire inner surface of afbodyof cementitious mix positioned within `the fchamber 30 will be subjected to negative `Vpressures, upon rotation of the outer form and fthe mix, 4to draw 'off or remove excess liquids within the mix by vway of the perforations 38, :andownwardly and outwardly through the cen- `trally'disposed passageway v40 to be discharged ""fromy the-suction1pump-f41. To prevent the discharge or withdrawal Yof solid particles from 4Within the mix vdisposed within the` chamber 3B, the interior surface of the side walls of the core rislprovided-.with a screened or mesh covering 49 Ls-Whch'prevents the passage of solid materials through theperforation, but at the same time allows excess liquid to be drawn olf by means 'offthe reduced pressures within the interior of theecore. AlsoI disposed within the core 29, and rigidly attachedto the interior side walls there- "offis'zin/electrically operated high frequency vi- "bra'torfmechanism, indicated by the numeral 5S.-

=Electrical current is supplied the vibratorfmechanism by means of an electrical lead conduit 5l introduced interiorly of the core through a "sealed opening-52 provided in the upper end wall "36 thereof. Thevibrator mechanismf serves upon operation to impart high frequency vibrations-within the core 219 whereby the adjacent lcementitious'mix is subjected to such'vibration 'to'improve the subsequent density qualities.v withvinlthe'inished pipe formed by the present machine.

v*litwill be seen, that'due to the simultaneous application of vreduced pressures to the mix during rotation thereof, -with the added feature of 4vibrationfsubstantially the entire inner surface rof-'the mix-disposedbetween the inner and outer xforms-is subjected-to the reduced pressures as the-'mix revolves past the perforated areas of the Acore, lthe same `being subjected to a con- F`stant churning `action duey to the relative movement btween the mix and the stationary core, thus` insuring lan even mixture resulting in a pipe section possessing uniform density from top to bottom.

In operation, the perforate inner core 29 is first lowered to its operating position, as disclosed in Fig. 3, thereby establishing an air-tight communication between the interior chamber of the vcore and the suction pump 41. At this time, fthe outer-form 26 and its associated pallet `33 rare assembled in their respective order upon-the turntable I4 in spaced concentric relationl tothe y,outer-walls of the core, and defining therewith the .annular cylindrical mix-receiving chamber E30. Rotation is then imparted to the turn table S44, by means of its associated electric motor, swhereuponithe outer form and pallet are caused :"torotateraboutthe relatively stationary core, at '.whichitime-.a.wetncementitious mix is introduced vwithin Athev chamber 4.30during the rotation, in an even andfmetered flow .byflway of the feed spout 3l. It will be understood, that due to the rotation of the outer form and its associated pals)et during the-metered introduction ofthe mix` s Vthrough fthe feed spout, `the f' level of the mix lwithin the chamber -30 will be evenlydistribut- V-ed'constant, thereby insuring a predetermined rise of the mix per revolution of the outer form which causes the vmixtofbe packed into -a uniform and dense mass from the bottom totheftop of -the chamber. During the initial filling 0f the 'mix-receiving chamber, considerable excess liquid'will be drained'from the mix through'the perforationsof thecore and will pass byv gravity outwardly through the suction-pump 41. As `the level of the mix within the` chamber rises above the upper perforations of the core, `the metering valve 32a, associated with the feed hopper 32,'is closed to-curtail the flow of mix kwithin the chamber. At this time'the 'suction' pump f41 is operated to provide decreased pressures within the-core during the rotation of "the mix andthe outer form,` whereby excess liquids are forced by atmospheric pressure present at the opposite side of the mix, inwardly through ithe perforations of the core to be sucked .downwardly and outwardly of theinterior chamber by way ofthe suction passage 40, and to be ultimately discharged from the pump 41. This .operation should be allowed to continue for asufficient time to insure the removal of substantially all of the excess liquid present within the mix. At this time,.the mix within the chamber `should be sufficiently dry and should possess sufficient body and strength to be able to retain its shape uponremoval of the core therefrom. Afterthe complete evacuation of the exrcess liquid from the mix, rotation of the turn table is precluded, and the pump `41 stoppedat vwhich time the core r3l) is elevated by the winch .mechanism 22 to leave the initially preformed pipe section standing .upon the pallet 33 and within the outer form 26. During the elevation of the core, the lowermost peripheral edge of thecore, which is unperforated, will tend vto smooth the inner surface of the preformed pipe section as the same is withdrawn through the center thereof, it being understood that a certain amount of roughness Within the inner surface ofthe pipe accompanies the rotation thereof past the perforations of the core, but as the 4latter is withdrawn upwardly the smooth lower vedge of the core tends toseal andrnish the in- 'ner surface of the pipe. The initially formed lpipe section, with its associated pallet and outer form may then be removed to a remote position from the machine Hto allow the same to Ifinally set andcure before the removal therefrom of the outer'core andthe pallet.y At this time the '.machinemay again be assembled with the aid yofan additional outer form and pallet'to perform the operating cycle just described.

`While the cylindrical outer form '26 of the present machine has been disclosed in an imfperforate form, the same may be advantageously yformed in a perforate condition, as shown in Figf? of the drawings. 'In this form, an outer Iperforated form 53 vreplaces the `heretofore described imperforate vouter form, and may beradvantageously provided on either side with a web of screening material disposed adjacent its perforations in order to prevent the passage of solids therethrough. The use of this type form enables ka 'certainamount of Vthe excess liquids within "a wet cementitious mix to pass both by gravity, .during initial filling operation, and by centrifugal -forces set up within the mix during lthe rotation thereof, from the body of mix, as well as'being l"drawn out'vby" the` suction process. Furthenzthe use of a perforate outer form providesan increased area upon which atmospheric pressures will act to facilitate the withdrawal of excess liquids through the core.

In the foregoing specification, the terms wet and dry mix are intended to differentiate between the relative percentages of water used in different types of mixes, or in other words, the water ratio of a mix. Normally, a dry mix contains approximately three gallons of water per one hundred pound bag of cement, and produces a relatively cohesive non-fluid mass, whereas a wet mix contains approximately f'lve to six gallons of water per one hundred pound bag of cement. As a percentage ratio, a dry mix approximates one part water to five parts by weight of cement, and wet mix approximates one part water to threeparts by weight of cement, and provides a generally semi-fluid mass capable of assuming the shape of a receptacle into which it may be poured. The term cementitious mix is intended to include all types of mixes which contain the essential constituent of cement. whether sand, gravel, stone, asbestos or other fibres be added with the cement and water constituents. The present machine and methods readily lend themselves to the production of asbestos pipe, wherein no stone is employed in the original mix, such pipe being generally known commercially under the trade name of Transite.

In view of the foregoing, it will be seen that the present invention provides a mechanically eicient, useful, and novel machine for the production of concrete pipe from wet cementitious mixes. Further the present invention sets forth useful and efficient methods for forming concrete pipe from such mixes, the same providing for the formation of concrete pipe and other molded bodies possessed of extremely high structural strength, and having a smooth and even surface finish. In use, machines formed in accordance with the present invention entirely eliminate the necessity for complex and mechanically inefficient tamping or packing apparatus, thereby considerably reducing the cost of manufacture and operation of pipe-forming machines of the. character heretofore utilized in the industry. Also, by using negative pressures in conjunction with the wet mix, the initial forming period of the pipe' is greatly reduced as compared with I present day methods, which results in economical and eicient overall operations. Further, the present invention contemplates a multiple station machine embodying a plurality of pipe-forming assemblies utilizing common driving and pressure reducing apparatus. The present invention is also characterized by its adaptability to use with previous types of pipe-forming machines by simple modification to the core structure, the turn table, and the addition of the suction-creating apparatus.

While a preferred form of the present invention has been disclosed in detail, it will be mani- 'fest that various modifications, as to details of construction, are possible without departing from the vscope of the following claims.

I claim:

1. In a concrete pipe-forming machine; a substantially horizontally disposed rotary turntable; a vertically arranged cylindrical outer form carried for rotation with said turntable; a socket member positioned axially of said turntable; a vertically arranged cylindrical inner core formed ,with a perforate side wall and a substantially enclosed inner chamber in communication with the Aperforations of the side wall; means connected with the upper end of said core for moving the latter axially of said outer form, said core being movable to a positionof spaced concentricity with respect to said outer form and defining therewith an annular pipe-forming chamber for the reception of a cementitious mix; conduit means projee-ting axially outwardly from the lower end of said core and communicating with the inner chamber thereof, said conduit means being receivable within said socket member when said core occupies its position of concentricity with respect to said outer form; and vacuum-producing means communicating with said socket member and operable to establish subatmospheric pressures within the inner chamber of said core y upon engagement of said conduit means and said socket member whereby to draw oi excess fluids present in a cementitious mix positioned in said iiuids from said .mix and to compact the same within the chamber; withdrawing the excess fluids extracted from the mix from. the pipeforming chamber; and continuing the movement of said mix relative to said one of the forms until said mix attains a plastic semi-solid consistency.

3. The method of forming concrete articles which comprises depositing a fluid cementitious mix containing an excess of plasticizing liquids within a molding chamber defined on one side by a stationary form; causing said mix to move relative to and in Contact with said'stationary form to compact said mix within said chamber; subjecting said mix during movement thereof to subatmospheric pressures acting through said stationary form to extract excess liquids therefrom; and withdrawing excess liquids extracted from said mix from said chamber and continuing the movement thereof relative to said stationary form until said mix attains a plastic semi-solid consistency.

HECTOR X. ESCHENBRENNER.-

REFERENCES CITED The following references are of record inthe le of this patent:

UNITED STATES PATENTS Number Name Date 1,000,638 Stewart Aug. 15, 1911 1,275,353 Zwicker Aug. 13, 1918 1,655,431 Miller Jan. 10, 1928 1,810,583 Tuerck June 16, 1931 1,989,409 Gordon Jan. 29, 1935 2,091,385 Trickey Aug. 31, 1937 2,296,018 Boyle Sept. 15, 1942 2,356,852 Hutchinson Aug. 29, 1944 2,369,488 Perry Feb. 13, 1945 2,434,690 Ferla Jan. 20, 1948 2,536,364 Guy et al. Jan. 2, 1951 FOREIGN PATENTS Number Countryl Date 28,648 .Australia Aug. 2 f1, 1,931 

